CHAPTER XV. 



CONIFERS. 



The ovules of the Coniferae, however much they may differ 

 in their position and mode of attachment, exhibit the greatest 

 uniformity in their internal structure. A simple, some- 

 what fleshy integument, surrounds a short and thick nu- 

 cleus formed of delicate cellular tissue, leaving open a 

 wide micropyle-canal. In the anatropal ovules of the 

 Abietineae the division between nucleus and integument 

 extends downwards only for a short distance (PI. L1X, 

 fig. 10) ; the mouth of the ovule widens considerably above 

 the apex of the nucleus, parallel to the spermophore, and 

 appears as a transverse fissure. In Finns sylvestris and 

 P. strobus the nucleus exhibits a very remarkable depression 

 of its apex; in Pinus bahamea (PL LIX, figs. 10, 11), 

 the depression is less manifest. The nucleus in Juniperus 

 and Thuja increases in diameter towards the apex : in 

 both, the apex exhibits a depression, which however in Juni- 

 perus is but slight (PI. LXIV, fig. 5). Lastly, the nucleus 

 of Taxus, which is far larger than that of any other indi- 

 genous Conifer, is quite like that of most phaenogams, 

 in its oval form, and in the separation between its nucleus 

 and integument, which extends to the base of the ovule 

 (PI. LXIII, fig. 1). 



The nucleus at the time of the shedding of the pollen 

 consists of delicate- walled cells filled with granular muci- 

 lage. Deep in its interior — in the Abietineae and in Juni- 

 perus, underneath the place where the integuments and 

 the nucleus amalgamate; higher up in Thuja, and still 



